Through-flow rotary-piston hydraulic motor



United States Patent O U.S. Cl. 91-56 3 Claims ABSTRACT OF THE DISCLOSURE This motor has an elongated tubular casing body with a bored head at one end through which a power output shaft passes and has a hollow head at the other end containing an internally-lobed stator and an externallylobed rotor of one less lobe meshing therewith and drivingly connected to a rotary liuid distributor or valve member by means of a double-headed splined powertransmitting shaft. The rotary valve member is in turn connected to the power output shaft and contains circumferentially-spaced longitudinal passageways which communicate successively with casing side ports for respectively receiving pressure uid and discharging uid.

The iluid flow from the valve member to the statorrotor chamber is in one direction only rather than oscillating back-and-forth as in the conventional prior fluid motors of the rotary-piston orbital type. As the hydraulic fluid ows from the pump through the motor, it thus provides external cooling of the fluid as Well as making possible the elimination, by filtering, of foreign matter which in the conventional rotary piston motor is entrapped within the rotary valve recesses or in the statorrotor chamber and can stall such a prior motor. Moreover, this through-How motor requires less oil pressure to force the fluid into and out of the stator-rotor chamber.

SUMMARY OF THE INVENTION In this gear-rotor orbital motor, the rotary fluid distributor, which is drivingly connected to the rotor, has a pair of axially-spaced annular fluid channels disposed in constant communication with the fluid inlet and outlet ports of the motor casing. It also has short axially-spaced longitudinal fluid passageways extending in the same direction toward the stator and rotor. These passageways, during rotation of the distributor, communicate with axially-spaced casing ports which in turn open into circumferentially-spaced longitudinal casing passageways communicating with the recesses or pockets between the internal teeth or lobes of the stator. As a result, the hydraulic iiuid always travels in the same direction during its passage through the motor and does not oscillate therein.

In the drawings:

FIGURE 1 is a central vertical section through a through-flow rotary-piston hydraulic motor, according to one form of the invention;

FIGURE 2 is a fragmentary vertical section similar to the central portion of FIGURE l, but with the rotary valve member shown in side elevation rather than in longitudinal section;

FIGURE 3 is a horizontal section through the statorrotor chamber, taken along the line 3-3 in FIGURE 1; and

FIGURE 4 is a horizontal section through the casing body rotary valve member and power-transmitting shaft, taken along the line 4-4 in FIGURE l.

Referring to the drawings in detail, FIGURES l to 4 inclusive show a through-flow rotary-piston hydraulic motor, generally designated as consisting generally of 3,494,255 Patented Feb. 10, 1970 ice' a multi-part casing 12 within which is mounted a statorrotor unit 14 drivingly connected by a double-headed splined power transmitter or motion-transmitting shaft 16 to a power output shaft 18 integral with which is a rotary fluid distributor or distributing valve 20. The multi-part casing 12 in turn consists of a tubular composite casing body, generally designated 22, the lower end of which is closed by an apertured lower end plate 24 bolted thereto while the other end is closed by a spacer or partition plate 26 above which is mounted an upper end closure plate 28. The upper end closure plate 28, the stator 30, and the partition disc 26 are bolted to the upper end of the casing body 22. The composite casing body 22, which consists of tubular outer and inner casing body components 32 and 34 and the method of making it are described and claimed in the copending application of Ferdinand I. Henkel, Ser. No. 689,209 liled aJn. 16, 1968 for Composite Fluid Pressure Pump or Motor Casing Body and Method of Making the Same.

The outer casing body component 32 is of approximately cylindrical shape and is provided on one side with spaced lower and upper bosses 38 and 40` containing threaded hydraulic iiuid supply and discharge ports 42 and 44 adapted to be connected to correspondinglythreaded uid conduits (not shown). The outer body component 32 is provided with a longitudinal slightly-tapered outer bore 46 having a bottom opening 48 of slightly larger diameter than its top opening 50. This taper is of approximately four-thousandths of an inch (0.004 inch) dimension to provide the desired locking effect. The inner component 34 is of approximately hollow cylindrical shape but its external surface 52 is slightly tapered by the same amount as the tapered bore 46 of the outer body component 32.

The inner component 34 is provided with radial ports 56 and 58 aligned with the tapered ports 42 and 44 in the outer component 32 when the two components 32 and 34 have been assembled as described below. The inner component 34 is likewise provided with iive circumferentiallyspaced longitudinally-extending external grooves or recesses 60 formed for convenience of machining as by a milling cutter in a milling machine. The upper ends of the grooves 60 are open in order to transmit fluid in timed relationship to and from the rotary piston stator-rotor unit 14 of the motor 10, located above the partition plate 26. The inner body component 34 is additionally provided with longitudinally-spaced lower and upper radial intermediate fluid ports 64 and 66 formed as by drilling in a drilling machine, and directed approximately radially to the longitudinal circumferential grooves 60. The lower transverse ports 64 are spaced circumferentially apart from one another, likewise the upper transverse ports 66. The inner ends of the ports 56, 58, 64 and 66 open into a central valve bore 68.

The opposite ends of the inner body component 34 between the multiple longitudinal grooves 60 are provided with multiple longitudinal threaded fastener holes 70 formed as by drilling and located between the grooves 60 in alternating sequence. The fastener holes 70 are incomplete in that they are of slightly less than full circular cross-section. The fastener holes 70 are bored before assembly but not threaded until after assembly.

In assembling the outer and inner body components 32 and 34 to form the composite casing body 22, the smaller end of the inner component 34 is pushed into the larger end opening 48 of the tapered bore 46 in the outer component 32, and the components 32 and 34 rotated relatively to one another so that the inner component ports 56 and 58 are aligned coaxially with the outer component ports 42 and 44. The casing body components 32 and 34 are then pressed snugly together and the fastener 1oles 70 again drilled to make them of completely cir- :ular cross-section extending into the outer body com- Jonent 32 adjacent its opposite ends. The fastener holes and their continuations in the outer component 32 are low threaded to receive correspondingly-threaded fas- :eners 71. These fastener holes 70 and bolts 71, by exending into both components 32 and 34, prevent relaive rotation therebetween.

The apertured end plate 24 is drilled at circumferenially-spaced locations for the passage of the bolts 71 vhich secure it to the lower end of the casing body 22 tnd is bored centrally at 72 for the passage of the outer :nd portion 74 of the power output shaft 18. The bore '2 is also grooved to receive a packing ring 76 (FIGURE and the end plate 24 is similarly grooved adjacent the lpper end of a counterbore 78 to receive a packing ring S0. In addition, the lower or outer face of the end plate `4 is counterbored to receive a sealing ring 82. These acking rings 76, 80 and 82 prevent leakage around the educed diameter outer end portion 74 of the power shaft 8 and around the enlarged-diameter cylindrical portion t4 integral with the power output shaft 18 and containing he rotary valve member 85.

Mounted between the reduced diameter shaft portion 4 and its cylindrical enlargement 84 containing the otary valve member 8S of the rotary fluid distributing alve 20 is a metal thrust ring 86 which closes the outer nd of a transverse passageway 88. The latter leads by lay of a longitudinal lubricant passageway to an elonated counterbore 92 which is open at its upper end and ear its lower end irs provided ywith an internally-toothed nnular spline portion 94 (FIGURE l). The upper face f the ring 86 opens into a grooved portion adjacent the lnction of the shaft 18 and its enlargement 84 and there ngages a radial needle roller thrust bearing 96 with yay of a longitudinal lubricant passageway 90 to an elonidial rollers 98 which are lubricated by oil flowing therei through the passageways 88 and 90, assuming as is sual, that the hydraulic working fluid is oil. The body 2 has a like bearing 96 at its upper end.

The rotary valve member 85 in alignment with the Jrts 56 and 58 is provided with axially-spaced lower and pper annular grooves or fluid channels 100 and 102 reiectively. Extending longitudinally upward from the wer annular grooves 100 and upper annular grooves )2 are elongated distributing passageways 104 and 106 :spectively (FIGURE 2) which are spaced circumferltially at equal intervals around the periphery of the llargement 14. In addition the upper passageways 106 'e spaced circumferentially relatively to the lower pastgeways 104 so as to stagger or alternate the upper pas- .geways 106 relatively to the lower passageways 104. he passageways 104 and 106 at their upper ends move to registry with the ports 64 and 66 (FIGURE 2) in sponse to rotation of the rotary valve member 85.

The upper ends of the five grooves or longitudinal pasgeways 60 open into five aligned ports 108 extending rough the partition plate 26 at the same circumferen- 11 spacings as the grooves 60, and the ports 108 in turn )ening into the five radial recesses 110 of the approxiately five-pointed star-shaped stator chamber 112 (FIG- RE 3) of the stator 30. The stator chamber 112, be- Yeen alternate recesses 110, has inwardly-convex pro- :tions 114. The stator chamber 112 is closed on its )per side by the upper end closure plate 28 secured to e casing body 12 by the bolts 71.

Mounted for simultaneous rotation and orbital travel thin the stator chamber 112 is a four-lobed rotor 116,

e round-ended lobes 118 of Iwhich (FIGURE 3) have lling sealing contact with the side walls of the pockets ,0 and convex projections 114 of the stator 30. Between e lobes 118, which are four in number, are found ncave portions which provide clearance with the jacent convex walls 114 as the rotor lobes 118 engage Cil and roll along the convex projections 114. It will be understood that the construction shown is not limited to a stator 30 with ve recesses and a rotor 116 with four lobes, because a greater number thereof may be employed, with the understanding that the rotor 116 always has one less lobe 118 and concave portion 120 than the number of recesses 110 and projections 114 in the stator 30.

The rotor 116 in its center is provided with an internally-splined bore 122 which in turn is rockingly engaged by the correspondingly-splined convex upper head 124 of the double-headed splined motion-transmitting shaft 16, the convexly-splined lower head 126 of which rockingly engages the lower internally-toothed splined portion 94 at the lower end of the counterbore 92 in the rotary valve member 20.

In order to mount the motor 10 upon a machine (not shown) which it is to drive, the lower end plate 24 is provided with circumferentially-spaced bolt holes 128, and the output power shaft 74 is provided with a key seat 130 adapted to receive a conventional Woodruff key 132 which in turn drivingly engages a conventional longitudinal keyway groove (not shown )in the machine element to be driven by the motor 10'.

Prior to the operation of. the through-flow hydraulic motor 10, the lower port 42 is connected to a source of pressure fluid, preferably hydraulic while the upper port 44 is connected to either the fluid reservoir or to the suction side of the pump or hydraulic circuit furnishing the pressure uid. The pressure fluid flows from the supply port 42 through the port 56 into the lower annular channel 100 whence it passes upward into the four circumferentially-spaced lower pockets 104 and thence through any one of the five lower ports 64 which happens to be registered with any one of the pockets 104 at that instant. From the momentarily communicating lower port 64 and pocket 104, the pressure fluid flows upward through the groove 60 adjacent thereto and through the aligned port 108 in the partition disc 26 into the stator chamber 112 where it acts against the side of the nearest lobe 118, pushing it in a circumferential direction. Meanwhile the fluid from the opposite side of the lobe 118 is exhausted through another of the ports 108 behind the particular lobe 118 and transmitted through the upper port 66 thereof which is temporarily in registry with one of the upper pockets 106 (FIGURE 2) and thence into and through the upper annular channel 102, out through the upper outlet port 58 and threaded port 44 into the return conduit (not shown) leading back to the fluid reservoir or suction side of the pump, as the case may be.

This combined action of pressure upon one side of a lobe 118 and suction on the other side thereof while the tip of the lobe 118 is in rolling sealing engagement with the adjacent convex side wall 114 of the stator chamber 112 imparts rotary motion to the rotor 116 (FIGURE 3).

' This in turn through the splined connections 122 and 94 of the heads 124 and 126 of the motion-transmitting shaft 16 imparts rotation to the rotary fluid distributing valve 20 and to the power output shaft 18 integral therewith. This rotation rotates the rotary fluid distributing valve 20 so that its lower and upper fluid pockets 104 and 106 come successively into registry with ports 64 and 66 in different longitudinal grooves 60 so as to continue rotation of the rotor 116 and rotary fluid distributing valve 20. At the same time, the rotor 116 by the rolling action of its lobes 118 around the stator 30 describes an orbital path which in turn imparts an oscillating motion to the motion-transmitting shaft 16 around the pivot connection formed by its splined lower head 126 with the internal splining 94 at the lower end of the elongated counterbore 92. Moreover, the rotation of the rotor 116 imparts rotation to the rotary valve member 20 and power output shaft 18 at a speed reduction ratio equivalent to the speed reduction accomplished by the internal-external gear action of the stator 30 and rotor 116.

Thus, the working fluid in performing its power generation flows entirely through the motor from the pressure fluid inlet port 42 to the fluid outlet port 44 instead of merely oscillating back and forth between the stator chamber and the oppositely-directed pockets found in prior rotary piston orbital motors, such as the motor described in FIGURES 9 to 15 inclusive of the abovementioned Henkel Patent 3,261,235 of July 19, 1966 and claimed therein. This through-flow result obtained by the construction and arrangement of the present motor therefore achieves the correspondingly improved operation and results of enabling the working fluid to be cooled and ltered externally of the motor 10, thereby reducing wear, stalling of the motor from foreign matter particles, enhancing starting thereof and enabling the motor to be operated by working fluid at lower pressures than have hitherto been obtainable. The same through-flow action of the working fluid also eliminates the 180-degree turns of the working fluid which occurred in the abovedescribed prior rotary-piston orbital motors and still further reduces the pressure required to force the oil or other working fluid through the present motor as contrasted with the higher pressure required to force the oil into prior motors where it was required to reverse its path while moving back and forth within the pockets in its rotary valve and stator chamber. As a consequence, the length of the path of the oil within the present motor is considerably less than the length of path traversed within the above-mentioned prior motors.

I claim:

1. A through-flow comprising a casing structure having a pressure fluid supply port and a fluid discharge port therein,

an open-centered stator connected to said casing structure and having circumferentially-spaced multiple alternate internal recesses and convex projections,

a rotor having multiple circumferentially-spaced lobes numbering at least one less than the number of lobes of said stator and projecting outwardly therefrom into rolling enQaUement with said recesses and projections for rotational and orbital movement relatively to said stator,

a rotary hydraulic fluid distributor simultaneously supplying pressure fluid from said fluid supply port t0 said circumferentially-spaced recesses and withdrawing exhaust fluid from said recesses to said fluid discharge port,

a rotary power-transmitter operatively connecting said rotor to said fluid distributor,

and a rotary power output shaft drivingly connected to said fluid distributor for rotation unitarily therewith,

said casing structure having multiple longitudinally-extending circu'mferentially-spaced intermediate fluid passageways successively connectrotary-piston hydraulic motor,

ing said fluid supply port through said fluid distributor to said stator recesses and connecting said stator recesses through said fluid distributor to said fluid discharge port in response to rotation of said uid distributor, said rotary fluid distributor containing two axiallyspaced sets of circumferentially-spaced distributor fluid passageways, one set thereof connecting said pressure fluid supply port to said intermediate fluid passageways and the other set thereof connecting said intermediate fluid passageways to said fluid discharge port in timed relationship with the rotation of said fluid distributor, said casing structure having two axially-spaced sets of intermediate fluid ports opening into said intermediate fluid passageways, the ports of each of said sets being spaced circumferentially apart from one another and said two sets of distributor fluid passageways being brought into registry with their respective intermediate fluid ports in response to rotation of said fluid distributor, said rotary fluid distributor having a pair of axially-spaced annular fluid channels therein communicating respectively with said fluid supply and discharge ports,

said two sets of distributor fluid passageways communicating respectively with said pair of axially-spaced annular fluid channels, said two sets of distributor fluid passageways extending axially in the same direction from their respective annular fluid channels toward said stator and rotor.

2. A through-flow rotary-piston hydraulic motor according to claim 1, wherein said distributor fluid passageways terminate short of the annular fluid channels to which they are not connected.

3. A through-flow rotary-piston hydraulic motor, according to claim 1, wherein the passageways of one set of said distributor fluid passageways are disposed out of axial alignment with the passageways of the other set thereof.

References Cited UNITED STATES PATENTS Re. 25,291 12/1962 Charlson 91-56 3,261,235 7/1966 Henkel 91-56 X 3,270,681 9/1966 Charlson 103-130 3,283,723 11/1966 Charlson 103-130 3,377,873 4/1968 Patterson 91-56 X MARTIN P. SCHWADRON, Primary Examiner IRWIN C. COHEN, Assistant Examiner 

